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Article: The "x-Factor" index: A new parameter for the assessment of adolescent idiopathic scoliosis correction
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TitleThe "x-Factor" index: A new parameter for the assessment of adolescent idiopathic scoliosis correction
 
AuthorsSun, YQ2
Samartzis, D1
Cheung, KMC1
Wong, YW1
Luk, KDK1
 
KeywordsCorrection
Curve
Flexibility
Fulcrum bending
Index
Radiograph
Rate
Scoliosis
X-Factor
 
Issue Date2011
 
PublisherSpringer. The Journal's web site is located at http://www.springer.com/medicine/orthopedics/journal/586
 
CitationEuropean Spine Journal, 2011, v. 20 n. 1, p. 144-150 [How to Cite?]
DOI: http://dx.doi.org/10.1007/s00586-010-1534-3
 
AbstractThe correction rate (CR) and fulcrum bending correction index (FBCI) based on the fulcrum bending radiograph (FBR) were parameters introduced to measure the curve correcting ability; however, such parameters do not account for contributions by various, potential extraneous "X-Factors" (e.g. surgical technique, type and power of the instrumentation, anesthetic technique, etc.) involved in curve correction. As such, the purpose of the following study was to propose the concept of the "X-Factor Index" (XFI) as a new parameter for the assessment of the correcting ability of adolescent idiopathic scoliosis (AIS). A historical cohort radiographic analysis of the FBR in the setting of hook systems in AIS patients (Luk et al. in Spine 23:2303-2307, 1998) was performed to illustrate the concept of XFI. Thirty-five patients with AIS of the thoracic spine undergoing surgical correction were involved in the analysis. Plain posteroanterior (PA) plain radiographs were utilized and Cobb angles were obtained for each patient. Pre- and postoperative PA angles on standing radiograph and preoperative fulcrum bending angles were obtained for each patient. The fulcrum flexibility, curve CR, and FBCI were determined for all patients. The difference between the preoperative fulcrum bending angle and postoperative PA angle was defined as AngleXF, which accounted for the correction contributed by "X-Factors". The XFI, designed to measure the curve correcting ability, was calculated by dividing Angle XF by the fulcrum flexibility. The XFI was compared with the curve CR and FBCI by re-evaluating the original data in the original paper (Luk et al. in Spine 23:2303-2307, 1998). The mean standing PA and FBR alignments of the main thoracic curve were 58.3° and 24.5°, respectively. The mean fulcrum flexibility was 58.8%. The mean postoperative standing PA alignment was 24.7°. The mean curve CR was 58.0% and the mean FBCI was 101.1%. The mean XFI was noted as 1.03%. The CR was significantly positively correlated to curve flexibility (r = 0.66; p < 0.01).The FBCI (r = -0.47; p = 0.005) and the XFI (r = -0.45; p = 0.007) were significantly negatively correlated to curve flexibility. The CR was not correlated to AngleXF (r = 0.29; p = 0.089).The FBCI (r = 0.97; p < 0.01) and the XFI (r = 0.961; p < 0.01) were significantly positively correlated to AngleXF. Variation in XFI was noted in some cases originally presenting with same FBCI values. The XFI attempts to quantify the curve correcting ability as contributed by "X-Factors" in the treatment of thoracic AIS. This index may be a valued added parameter to accompany the FBCI for comparing curve correction ability among different series of patients, instrumentation, and surgeons. It is recommended that the XFI should be used to document curve correction, compare between different techniques, and used to improve curve correction for the patient. © 2010 Springer-Verlag.
 
ISSN0940-6719
2012 Impact Factor: 2.133
2012 SCImago Journal Rankings: 1.311
 
DOIhttp://dx.doi.org/10.1007/s00586-010-1534-3
 
PubMed Central IDPMC3036025
 
ISI Accession Number IDWOS:000285972500020
 
ReferencesReferences in Scopus
 
DC FieldValue
dc.contributor.authorSun, YQ
 
dc.contributor.authorSamartzis, D
 
dc.contributor.authorCheung, KMC
 
dc.contributor.authorWong, YW
 
dc.contributor.authorLuk, KDK
 
dc.date.accessioned2010-09-22T05:04:07Z
 
dc.date.available2010-09-22T05:04:07Z
 
dc.date.issued2011
 
dc.description.abstractThe correction rate (CR) and fulcrum bending correction index (FBCI) based on the fulcrum bending radiograph (FBR) were parameters introduced to measure the curve correcting ability; however, such parameters do not account for contributions by various, potential extraneous "X-Factors" (e.g. surgical technique, type and power of the instrumentation, anesthetic technique, etc.) involved in curve correction. As such, the purpose of the following study was to propose the concept of the "X-Factor Index" (XFI) as a new parameter for the assessment of the correcting ability of adolescent idiopathic scoliosis (AIS). A historical cohort radiographic analysis of the FBR in the setting of hook systems in AIS patients (Luk et al. in Spine 23:2303-2307, 1998) was performed to illustrate the concept of XFI. Thirty-five patients with AIS of the thoracic spine undergoing surgical correction were involved in the analysis. Plain posteroanterior (PA) plain radiographs were utilized and Cobb angles were obtained for each patient. Pre- and postoperative PA angles on standing radiograph and preoperative fulcrum bending angles were obtained for each patient. The fulcrum flexibility, curve CR, and FBCI were determined for all patients. The difference between the preoperative fulcrum bending angle and postoperative PA angle was defined as AngleXF, which accounted for the correction contributed by "X-Factors". The XFI, designed to measure the curve correcting ability, was calculated by dividing Angle XF by the fulcrum flexibility. The XFI was compared with the curve CR and FBCI by re-evaluating the original data in the original paper (Luk et al. in Spine 23:2303-2307, 1998). The mean standing PA and FBR alignments of the main thoracic curve were 58.3° and 24.5°, respectively. The mean fulcrum flexibility was 58.8%. The mean postoperative standing PA alignment was 24.7°. The mean curve CR was 58.0% and the mean FBCI was 101.1%. The mean XFI was noted as 1.03%. The CR was significantly positively correlated to curve flexibility (r = 0.66; p < 0.01).The FBCI (r = -0.47; p = 0.005) and the XFI (r = -0.45; p = 0.007) were significantly negatively correlated to curve flexibility. The CR was not correlated to AngleXF (r = 0.29; p = 0.089).The FBCI (r = 0.97; p < 0.01) and the XFI (r = 0.961; p < 0.01) were significantly positively correlated to AngleXF. Variation in XFI was noted in some cases originally presenting with same FBCI values. The XFI attempts to quantify the curve correcting ability as contributed by "X-Factors" in the treatment of thoracic AIS. This index may be a valued added parameter to accompany the FBCI for comparing curve correction ability among different series of patients, instrumentation, and surgeons. It is recommended that the XFI should be used to document curve correction, compare between different techniques, and used to improve curve correction for the patient. © 2010 Springer-Verlag.
 
dc.description.naturelink_to_OA_fulltext
 
dc.identifier.citationEuropean Spine Journal, 2011, v. 20 n. 1, p. 144-150 [How to Cite?]
DOI: http://dx.doi.org/10.1007/s00586-010-1534-3
 
dc.identifier.citeulike7704596
 
dc.identifier.doihttp://dx.doi.org/10.1007/s00586-010-1534-3
 
dc.identifier.epage150
 
dc.identifier.hkuros173074
 
dc.identifier.isiWOS:000285972500020
 
dc.identifier.issn0940-6719
2012 Impact Factor: 2.133
2012 SCImago Journal Rankings: 1.311
 
dc.identifier.issue1
 
dc.identifier.openurl
 
dc.identifier.pmcidPMC3036025
 
dc.identifier.pmid20714756
 
dc.identifier.scopuseid_2-s2.0-78651502969
 
dc.identifier.spage144
 
dc.identifier.urihttp://hdl.handle.net/10722/92930
 
dc.identifier.volume20
 
dc.languageeng
 
dc.publisherSpringer. The Journal's web site is located at http://www.springer.com/medicine/orthopedics/journal/586
 
dc.publisher.placeGermany
 
dc.relation.ispartofEuropean Spine Journal
 
dc.relation.referencesReferences in Scopus
 
dc.rightsThe original publication is available at www.springerlink.com
 
dc.subject.meshBone Screws
 
dc.subject.meshRadiographic Image Interpretation, Computer-Assisted
 
dc.subject.meshRange of Motion, Articular
 
dc.subject.meshScoliosis - radiography - surgery
 
dc.subject.meshThoracic Vertebrae - radiography - surgery
 
dc.subjectCorrection
 
dc.subjectCurve
 
dc.subjectFlexibility
 
dc.subjectFulcrum bending
 
dc.subjectIndex
 
dc.subjectRadiograph
 
dc.subjectRate
 
dc.subjectScoliosis
 
dc.subjectX-Factor
 
dc.titleThe "x-Factor" index: A new parameter for the assessment of adolescent idiopathic scoliosis correction
 
dc.typeArticle
 
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<contributor.author>Samartzis, D</contributor.author>
<contributor.author>Cheung, KMC</contributor.author>
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<contributor.author>Luk, KDK</contributor.author>
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Author Affiliations
  1. The University of Hong Kong
  2. Beijing Ji Shui Tan Hospital